Bill Bryson Quote
Before, prior to. There is no difference between these two except length and a certain affectedness on the part of 'prior to.' To paraphrase Bernstein, if you would use 'posterior to' instead of 'after,' then by all means use 'prior to' instead of 'before.
Bryson's Dictionary for Writers and Editors (ed. Anchor, 2008) - ISBN: 9780767929110